The present invention relates to a separator-diffuser for a gas turbine engine, more particularly such a separator-diffuser having integral guide vanes.
Axial flow gas turbine engines typically comprise an oxidizer compressor consisting of a plurality of rotor wheels with a plurality of vane stages interposed between the rotor wheels. The guide vane stages guide the oxidizer flow into a generally axial flow path and through a diffuser which directs the oxidizer towards one or more fuel injection heads so that the oxidizer may be mixed with the fuel and ignited in a combustion chamber. In such gas turbine engines utilized as turbojet aircraft engines, it is known to provide two or more radially spaced, generally annular fuel injection head arrays which extend in annular fashion around the central axis of the turbojet engine. As is well known in the art, one annular array of fuel injection heads is used under low power conditions, while the other array of fuel injection heads is utilized in full power operating modes.
To ensure proper distribution of the oxidizer, typically air, a diffuser is located between the last guide vane stage and the fuel injection head arrays in order to direct portions of the oxidizer towards each of the annular arrays of fuel injection heads. Such known diffusers are located downstream of the final guide vane stage and upstream of the fuel injection heads. The oxidizer passing through the diffuser may also be directed such that portions bypass the fuel injection heads and, in known fashion, feeds the primary air zone of the combustion chamber and cools the walls of the combustion chamber.